I'm creating a fairly extensive Excel user form making use of several custom classes I've written. Things currently seem to work as expected, but sometimes when I close the form a process appears to still be running in the background.
I know this because after closing said form, sometimes a CPU core keeps running at full capacity, and when I click on a cell in my spreadsheet the value shown in the formula bar blinks rapidly, as if the spreadsheet were being repeatedly refreshed.
I've tried inserting breaks and debug statements in the Class_Terminate functions of each class (or at least all the big ones), and they all seem to deconstruct neatly. Furthermore, when I rest at a code break, everything halts as expected.
So, what gives? Is there a better way to isolate the problem? How can I find out what's still running after I close my userform?
Well, after some aggressive commenting and uncommenting, it seems like my error has to do with VBA's destructor functions, Class_Terminate().
I have a "WellReader" class within a "WellCollection" class, so when I terminate my WellCollection class, it destructs WellReader along with it. However, if I have Class_Terminate() defined for both classes, it throws my program into a loop (literally). Simply defining the functions causes the error, even if there's no code within them.
(Here's a related StackOverflow post that sheds some amount of light on this issue.)
So, while I'm not sure why both destructor functions won't work, for now I'll do without one. Thanks for everyone's help!